This invention relates in general to an optical scanning instrument, and more particularly to a multi-point scan architecture.
Confocal microendoscopy is an emerging technology that allows in situ confocal microscopic imaging of cells in live animals and humans. A number of approaches to confocal microendoscopy have been developed. The two most common methods are those that employ a coherent fiber optic bundle to relay the image plane of confocal microscope into the body, and those that build a miniaturized confocal microscope with the scanning mechanism into the distal tip of the flexible imaging device.
For the miniaturized confocal microscope method, see Dickensheets, D. L., et al., “Micromachined scanning confocal optical microscope,” Optics Letters 21, 764-766 (1996), Kiesslich R, et al., “Confocal laser endoscopy for diagnosing intraepithelial neoplasias and colorectal cancer in vivo,” Gastroenterology 127, 706-713 (2004). For the coherent fiber optic bundle, see Gmitro A. F., et al., “Confocal Microscopy Through a Fiber-Optic Imaging Bundle,” Optics Letters 18,565-567 (1993), Viellerobe, B., et al., “Mauna Kea technologies’ F400 prototype: a new tool for in vivo microscopic imaging during endoscopy,” Proceedings of SP1E. 6082 60820C (2006).
For the development of a confocal microendoscope utilizing a slit-scan fluorescence confocal microscope coupled to a fiber bundle with a custom miniature objective lens, see Rouse A. R., et al., “Design and demonstration of a miniature catheter for a confocal microendoscope,” Applied Optics 43, 5763-5771 (2004). This system operates at 30 frames per second and provides high quality fluorescent microscopic images of living tissue. This system has also been configured to allow multi-spectral imaging with essentially instantaneous switching between grayscale and multi-spectral modes of operation, see Rouse A. R., et al., “Design and demonstration of a miniature catheter for a confocal microendoscope,” Applied Optics 43, 5763-5771 (2004).
In the context of confocal microendoscopy, multi-spectral imaging provides a powerful capability allowing identification of multiple fluorophores and/or the sensing of subtle spectral shifts caused by tissue microenvironment.
A slit-scan confocal microscope represents a compromise between speed of operation and confocal imaging performance. Theory predicts that lateral resolution is maintained but axial resolution is reduced for a slit scan versus a point scan system. These theoretical results are for a non-scattering medium. Recent Monte Carlo simulation results show that performance degrades with depth for both point-scan and slit-scan systems, but that in the slit-scanning geometry the effects are severe enough to limit the practical imaging depth for in vivo imaging applications.
It is therefore desirable to provide an improved scan architecture in which the above disadvantages are not present.